Rheum plant named &#39;SCARLET KING&#39;

ABSTRACT

A new and distinct  Rheum  plant named ‘Scarlet King’ characterized by early dormancy break, exceptional frost resistance, and deep pearlescent red coloration of early season growth.

BOTANICAL DENOMINATION

Rheum spp.

VARIETY DESIGNATION

‘Scarlet King’

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Rheum (rhubarb) given the cultivar name ‘Scarlet King’. Rheum is in the family Polygonaceae. This new cultivar is a chance seedling of unknown origin that was discovered during an environmentally controlled indoor breeding program at Sconce Farms in Aurora, Oreg.

Compared to Rheum ‘Deacon’, the new cultivar breaks dormancy 2 or more weeks earlier in the Willamette Valley, Oreg. Compared to Rheum ‘Crimson’, the new cultivar breaks dormancy 3 or more weeks earlier in the Willamette Valley, Oreg. The new cultivar is also much more frost resistant than either ‘Deacon’ or ‘Crimson’ and has a deeper red color that extends throughout the stalk and into the veins of the leaves early in the growing season.

SUMMARY OF THE INVENTION

The following traits have been repeatedly observed and are determined to be the unique characteristics of the new cultivar. These characteristics in combination distinguish Rheum ‘Scarlet King’ as a new and distinct cultivar:

1. breaks dormancy in mid to late December in the Willamette Valley, Oreg.;

2. exceptional frost resistance and able to withstand freezing of the new growth without experiencing significant dieback or induced dormancy; and

3. new early season growth shows deep pearlescent red coloration on all sides of the stalk, with the deep pearlescent red coloration extending from the base of the stalk into the veins of the leaves.

This new cultivar has been reproduced only by asexual propagation (crown, or rhizome, division). Each of the progeny exhibits identical characteristics to the original plant. Asexual propagation using crown division, as done in Aurora, Oreg., shows that the foregoing characteristics and distinctions come true to form and are established and transmitted through succeeding propagations. The present invention has not been evaluated under all possible environmental conditions. The phenotype may vary with variations in environment without change in the genotype of the plant.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

FIG. 1 shows a Rheum ‘Scarlet King’ growing in the ground approximately 5 months after planting in a trial field in August in Aurora, Oreg.

FIG. 2 shows the stalks of Rheum ‘Scarlet King’ in August in Aurora, Oreg.

FIG. 3 shows stalk coloration of Rheum ‘Scarlet King’ harvested in Aurora, Oreg., early in the growing season.

DETAILED PLANT DESCRIPTION

The following is a detailed description of the new Rheum cultivar based on observations of five-month-old specimens growing in the ground in full sun under typical outdoor conditions in the trial fields in Aurora, Oreg. Observations were made in early August on plants that were planted in April of the same year. Aurora is Zone 8 on the USDA Hardiness map. Temperatures range from an average high of 83 degrees F. in August to an average low of 35 degrees F. in December. Normal rainfall in Aurora is 40.7 inches per year. The color descriptions are based upon The Royal Horticultural Society Colour Chart, 3^(rd) edition.

-   Plant:     -   -   Type.—herbaceous perennial.         -   Hardiness.—USDA Zones 3-8.         -   Size.—approximately 100 to 140 cm wide and 50 to 70 cm tall.         -   Form .—mound.         -   Vigor.—excellent. -   Leaf petiole (stalk):     -   -   Type.—Long and ascending with an approximately D-shaped             cross-section, often flat to slightly convex on the upper             side, especially early in the growing season.         -   Size.—Approximately 3-4 cm wide, 2-3 cm deep, and 40-50 cm             long.         -   Surface texture.—Striate, often with a pronounced ridge on             each edge of the upper side.         -   Color.—Somewhat pearlescent, strong yellowish pink 37A with             brilliant yellowish green 149C striae (as observed in             August). Generally darker and pinker at the proximal end and             progressively becoming lighter and more green at the distal             end. Stalks are darker, more pearlescent, and more uniform             in color earlier in the growing season, exhibiting a strong             reddish orange 40C coloration that extends over nearly the             entire length. -   Leaf:     -   -   Type.—Simple.         -   Shape.—Cordate.         -   Size.—Approximately 35-40 centimeters in length and breadth.         -   Arrangement.—Basal.         -   Margins.—Entire and wavy.         -   Surface texture.—Chartaceous.         -   Venation.—Cross-venulate.         -   Color.—Deep yellowish green 141A. -   Cold resistance: Highly resistant to frost damage. Survives moderate     to heavy frost, starting in late December, without significant     dieback and/or induced dormancy. -   Timing: In Aurora, Oreg., the new cultivar breaks dormancy 2 or more     weeks earlier than the closest commonly grown cultivar, ‘Deacon’.     The new cultivar is generally 20-30 cm tall when ‘Deacon’ breaks     dormancy. 

1. A new and distinct Rheum plant as herein illustrated and described. 